Heart Attack (Myocardial Infarction)

What Is a Heart Attack?

A heart attack, medically known as myocardial infarction (MI), occurs when blood flow through a coronary artery is severely reduced or interrupted, causing injury and death of heart muscle cells.

The most common cause is the formation of a blood clot following the rupture or erosion of an atherosclerotic plaque within a coronary artery.

When the heart muscle does not receive enough oxygen, myocardial damage begins to develop.

Restoring blood flow as quickly as possible is essential to limit permanent heart damage and reduce the risk of death.

A heart attack is a medical emergency requiring immediate evaluation and treatment.

What Are the Symptoms of a Heart Attack?

The most common symptom is chest pain or pressure.

Typical symptoms include:

• Pressure, tightness, or heaviness in the center of the chest
• Pain radiating to one or both arms
• Pain in the back, neck, jaw, or upper abdomen
• Shortness of breath
• Cold sweating
• Nausea or vomiting
• Sudden weakness
• Dizziness or fainting
• Unexplained severe fatigue

A heart attack does not always cause severe chest pain.

In women, older adults, and patients with diabetes, symptoms such as shortness of breath, nausea, fatigue, or back discomfort may be more prominent.

Some heart attacks occur with few or no noticeable symptoms.

What Causes a Heart Attack?

The most common cause is blood clot formation over an atherosclerotic plaque in a coronary artery.

Major risk factors include:

• Elevated LDL cholesterol
• Smoking
• Hypertension
• Diabetes mellitus
• Family history of premature myocardial infarction
• Advanced age
• Obesity
• Physical inactivity
• Chronic kidney disease
• Elevated lipoprotein(a)

Less common causes include coronary artery spasm, spontaneous coronary artery dissection, and coronary embolism.

What Are the Types of Heart Attack?

1. ST-Elevation Myocardial Infarction (STEMI)

STEMI is a type of myocardial infarction characterized by ST-segment elevation or equivalent findings of acute coronary occlusion on the ECG.

It is commonly associated with sudden and severe interruption of coronary blood flow.

Emergency coronary angiography and primary percutaneous coronary intervention (PCI) are the preferred treatment approach when available within the recommended time frame.

2. Non-ST-Elevation Myocardial Infarction (NSTEMI)

NSTEMI occurs when myocardial injury develops without persistent ST-segment elevation on the ECG.

Diagnosis is based on symptoms, ECG findings, and cardiac troponin measurements.

Treatment is guided by the patient's clinical risk. Early invasive coronary assessment may be necessary in high-risk patients.

How Is a Heart Attack Diagnosed?

1. Electrocardiogram (ECG)

An ECG is one of the first tests performed when a heart attack is suspected.

It helps identify electrical changes associated with myocardial ischemia or infarction.

However, a normal initial ECG does not completely exclude a heart attack.

2. Cardiac Troponin Testing

Troponin is an important blood marker of heart muscle injury.

High-sensitivity troponin assays and repeated measurements, when indicated, are used in diagnosis.

An elevated troponin level does not always mean that a heart attack has occurred. Results must be interpreted in the appropriate clinical context.

3. Echocardiography

Echocardiography evaluates ventricular function and regional wall motion abnormalities.

4. Coronary Angiography

Coronary angiography identifies narrowed or blocked coronary arteries.

Balloon angioplasty and stent implantation may be performed during the same procedure when appropriate.

How Is a Heart Attack Treated?

The main goals of treatment are to restore blood flow, limit myocardial damage, and prevent complications.

1. Emergency Coronary Angiography and Stent Implantation

In patients with STEMI, the blocked coronary artery should be reopened as quickly as possible.

The procedure is usually performed through an artery in the wrist or groin.

Balloon angioplasty and stent implantation may be used to restore coronary blood flow.

Not every myocardial infarction requires stent implantation; treatment depends on coronary anatomy and the clinical situation.

2. Fibrinolytic Therapy

For selected STEMI patients, fibrinolytic therapy may be considered when timely primary PCI is not available and there are no contraindications.

3. Medication

Depending on the patient's condition, treatment may include:

• Aspirin and other antiplatelet medications
• Anticoagulant medications
• High-intensity statin therapy
• Beta blockers
• ACE inhibitors or angiotensin receptor blockers
• Additional heart failure medications when indicated

Medication selection and treatment duration are individualized.

4. Cardiac Rehabilitation

Cardiac rehabilitation programs include supervised exercise, cardiovascular risk reduction, and lifestyle modification.

They are an important part of recovery after myocardial infarction.

What Complications Can Occur After a Heart Attack?

Potential complications include:

• Heart failure
• Ventricular tachycardia or ventricular fibrillation
• Significant bradycardia or AV block
• Cardiogenic shock
• Mitral regurgitation
• Rare mechanical complications involving the heart muscle

Close monitoring during the early phase of myocardial infarction is essential.

Can the Heart Fully Recover After a Heart Attack?

Recovery depends on the affected coronary artery, the duration of reduced blood flow, and how quickly treatment is initiated.

Early restoration of blood flow may preserve a substantial amount of heart muscle.

However, permanent myocardial damage may impair the heart's pumping function.

Can a Heart Attack Happen Again?

Yes. Patients who have experienced a myocardial infarction remain at increased risk of future cardiovascular events.

Important preventive measures include:

• Continuing prescribed cholesterol-lowering therapy
• Taking antiplatelet medications as directed
• Smoking cessation
• Blood pressure and diabetes management
• Regular cardiology follow-up
• Healthy eating and physical activity

Successful stent implantation does not eliminate the risk of another heart attack.

What Should You Do If You Suspect a Heart Attack?

If symptoms suggest a heart attack:

1. Call emergency medical services immediately.
2. Stop physical activity and rest in a safe position.
3. Do not attempt to drive yourself to the hospital.
4. Do not take new medications without guidance from a healthcare professional, apart from those previously prescribed for such situations.
5. If the person becomes unresponsive and is not breathing normally, begin CPR according to emergency dispatcher instructions.

Delays in treatment can increase permanent heart muscle damage.

Assoc. Prof. Sezen Bağlan Uzunget, MD
Cardiologist

This content is provided for general educational purposes. A suspected heart attack requires immediate medical assessment. Diagnosis and treatment should be individualized according to the patient's clinical condition.

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